diff -rupN includes/ajax.inc includes/ajax.inc
--- includes/ajax.inc	2009-05-15 12:20:06.000000000 +0200
+++ includes/ajax.inc	2009-05-15 12:37:09.000000000 +0200
@@ -36,6 +36,9 @@ function views_ajax() {
           $_GET['q'] = $path;
         }

+        // Allow other modules alter the view before it is executed.
+        drupal_alter('ajax_view', $view, $args);
+
         // Override the display's pager_element with the one actually used.
         if (isset($pager_element)) {
           $view->display[$display_id]->handler->set_option('pager_element', $pager_element);